JP2002354775A - Stator structure of claw pole stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator structure which can reduce a diameter and enhance the performance of a claw pole stepping motor. SOLUTION: The stator structure of the claw pole stepping motor comprises: a stator constituting a magnetic circuit that stator coils are disposed at yokes 2, 3 and pole teeth as processed soft magnetic steel sheets; and a rotor magnetic rotatably disposed in the stator. In the stator structure, ring pole teeth 41, 42 are separated from an outer yoke 2 and an inner yoke 3. Since the ring pole teeth are formed from the soft magnetic steel sheet stamped and rounded, a shape and a length of the pole teeth can be arbitrarily set and a small and long motor can be easily manufactured, has high output power and is excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a claw-pole type stepping motor, and more particularly, to a structure of a stator for reducing the size and performance of the motor and facilitating manufacture.

[0002]

2. Description of the Related Art In recent years, various types of equipment have been progressing in the direction of miniaturization and high performance, and the demand has not stopped. However, although sufficient space is provided as represented by a notebook personal computer, the height is limited to a certain level, and high-performance motor characteristics are required.

[0003] The claw-pole type stepping motor is a motor characterized by a relatively simple structure and capable of high-accuracy position control, but it has been difficult to reduce the size (diameter). It was mainly due to the formation of the pole teeth of the claw pole.

FIG. 9 shows a stator structure of a conventional general claw-pole type stepping motor. FIG. 9A is a perspective view showing a cutaway portion of the motor, and FIG. 9B is a main part of the stator. FIG. 4 is an exploded perspective view showing a yoke portion and a pole tooth portion.

In FIG. 9A, reference numeral 1 denotes a flange for mounting a motor, and an outer yoke portion 2 and an inner yoke portion 3 are manufactured by processing a soft magnetic steel sheet into a sheet metal. Has been formed. A coil 6 formed by winding a magnet wire around a bobbin 5 is disposed between the outer yoke 2 and the inner yoke 3. The pole teeth portions 4 of the outer yoke portion 2 and the inner yoke portion 3 are alternately arranged at intervals of 180 ° in electrical angle, form a magnetic circuit together with the coil 6, and have an A-phase stator 15 and a B-phase stator 1.
6. The two A-phase and B-phase stators 15 and 16 configured as described above are arranged one above the other back to back so that the A-phase and B-phase pole teeth portions 4 have an electrical angle of 90 ° from each other. The unit 17 is constituted. A lower flange 7 is attached to the outer yoke portion 2 of the lower B-phase stator 16 with a bearing 8 arranged at the center. Reference numeral 9 denotes a rotor magnet, and a sleeve 10 joins the rotor magnet 9 and the shaft 11.

[0006] The outer yoke 2 and the inner yoke 3 are shown in FIG.
As shown in (b), both were manufactured by sheet metal processing of a soft magnetic steel sheet, and the pole teeth portions 4 were formed integrally and then bent at the time of processing the yoke portions. Therefore, since the pole teeth 4 themselves are formed using the material of the hole provided in the center of the yoke, it is difficult to set the length and thickness of the pole teeth 4 arbitrarily. . When the motor diameter becomes small, it becomes more difficult to obtain a sufficiently long pole tooth portion, and the claw-pole type stepping motor is not mounted on a thin device of a certain size or more.

To solve this problem, there has been a proposal to configure the pole teeth as a separate part from the yoke, and an example is disclosed in JP-A-2000-50536. However, in this proposal, since each of the pole teeth is configured as a separate part, it is not very adaptable to an actual motor in terms of manufacturing labor and cost.

[0008]

As described above, in the claw pole type stepping motor, since the outer yoke portion 2, the inner yoke member 3, and the pole teeth portion 4 are integrally formed, the coil space becomes smaller as the diameter becomes smaller. In order to ensure this, it is necessary to reduce the thickness of the material, and it has been difficult to form pole teeth that are satisfactory in both strength and magnetic characteristics.
Therefore, instead of a claw-pole type stepping motor, a brushless DC motor must be added with an encoder serving as a position detector to perform position control, resulting in an expensive configuration.

However, in an environment surrounding a stepping motor, a high-performance magnet such as a rare-earth magnet is developed as a material for a rotor magnet opposed to a stator. And an appropriate structure was required.

Under these circumstances, an object of the present invention is to provide a stator structure which can easily manufacture a claw-pole type stepping motor which can be mounted on a thin device and can cope with a high-output motor. .

[0011]

In order to achieve the above object, a stator structure according to the present invention comprises a stator coil arranged in relation to a yoke portion and a pole tooth portion manufactured by processing a soft magnetic steel plate. In the stator structure of a claw-pole type stepping motor comprising a stator that forms a magnetic circuit and a rotor magnet that rotates in opposition to the pole teeth of the stator,
The pole teeth are formed separately from the yoke, and are punched out of a soft magnetic steel sheet into a shape forming the pole teeth to form pole teeth. The pole teeth are rounded and formed into a ring shape.

Further, the stator structure of the present invention is characterized in that a ring-shaped pole tooth portion is fitted and fixed in a circular hole provided in a yoke portion.

Further, the stator structure of the present invention is characterized in that a ring-shaped pole tooth portion is inserted into a circular hole provided in a yoke portion and both are fixed by welding.

Further, the stator structure of the present invention is characterized in that a ring-shaped pole tooth is inserted into a circular hole provided in a yoke and both are fixed with a mold resin.

Further, in the stator structure of the present invention, a protrusion is provided on the periphery of the circular hole of the yoke portion so as to protrude inward of the circular hole. It is characterized by having done.

Further, in the stator structure of the present invention, a projection is provided on the periphery of the circular hole of the yoke portion so as to protrude inward of the circular hole, and a notch is formed on the edge of the ring-shaped pole tooth opposite to the pole teeth. It is characterized in that the projection is engaged with the notch at the time of fixing.

Further, in the stator structure according to the present invention, a notch is provided on the periphery of the circular hole of the yoke portion, and a projection is provided on an end edge of the ring-shaped pole tooth portion opposite to the pole teeth, and the projection is formed when fixed. It is characterized by engaging with the notch.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

In the figure, the same or corresponding parts as in the conventional example shown in FIG. 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a stator structure in an embodiment of a claw-pole type stepping motor according to the present invention. FIG.
(B) shows a state where a yoke part and a pole tooth part which are main parts of the stator structure are disassembled.

The schematic structure of the stator structure according to the present invention is as follows.

As can be seen from FIG. 1 (b), the outer yoke 2 and the inner yoke 3 are not provided with pole teeth, but are circular holes 2a and 3 for mounting ring-shaped pole teeth 41 and 42 respectively.
Only a is provided. The pole teeth are manufactured separately from the yoke, and in the present embodiment, the pole teeth are punched out of a soft magnetic steel plate and rounded to be manufactured in a ring shape. That is,
To manufacture the ring-shaped pole teeth 41 and 42, first, a soft magnetic steel sheet 40 such as a galvanized steel sheet is punched into a shape having pole teeth 4a at regular intervals as shown in FIG.
Make A. The shape of the pole teeth 4a is substantially triangular or trapezoidal. Fig. 2 (b) shows the pole piece 4A thus manufactured.
The ring-shaped pole teeth 41,
42 is obtained. 21 is a joint (cut).

As shown in FIG. 1, a ring-shaped pole tooth 41 for the outer yoke 2 and a ring pole tooth 42 for the inner yoke 3 are prepared. 2
Are inserted and fixed in the circular hole 2a formed in the inner yoke portion 3 and the circular hole 3a formed in the inner yoke portion 3, respectively. FIG. 3 is a plan view showing a state where the ring-shaped pole teeth 42 are attached to the circular holes 3 a of the inner yoke 3. The ring-shaped pole teeth 42 may be fixed to the inner yoke 3 by a return force due to the spring property of the material,
It may be determined arbitrarily according to the use of the motor, for example, by fitting it into the circular hole 3a with a strong force and fixing it. However, it is preferable to perform welding in order to enhance the reliability of fixing (in FIG. Weld points are shown).

Referring again to FIG. 1 (b), the ring-shaped polar tooth 41 is similarly formed in the circular hole 2a of the cylindrical outer yoke 2.
Is fixed, and the bobbin 5 on which the coil 6 is wound in advance is inserted around the ring-shaped pole tooth portion 41 (omitted in FIG. 1B),
The inner yoke 3 is positioned over the outer yoke 2 by positioning each other so that the protrusion 3b formed on the peripheral edge of the inner yoke 3 is aligned with the receiving portion 2b formed on the upper edge of the outer yoke 2. By doing so, one stator is manufactured.

Next, a positioning method when the ring-shaped pole teeth are attached to the inner and outer yokes will be described by taking the inner yoke as an example.

FIG. 4 shows an embodiment of the positioning method according to the present invention. FIG. 4 is a plan view showing a state in which a ring-shaped pole part 42 is attached to the circular hole 3a of the inner yoke part 3 as in FIG.

A protrusion 3 is formed on the periphery of the circular hole 3a of the inner yoke 3.
c is provided, and the ring-shaped pole teeth 42 are inserted into the circular holes 3a.
The projection 3c is cut into the cut 21 of the ring-shaped pole tooth portion 42 when the ring-shaped pole tooth portion 4 is attached.
2 in the circumferential direction.

As described above, the pole teeth of the ring-shaped pole teeth 42 attached to the inner yoke section 3 and the pole teeth of the ring-shaped pole teeth section 41 attached to the outer yoke section 2 have an electrical angle of 180 °.
Must be alternately arranged at intervals of
As shown in (b), the projection 3 formed on the inner yoke 3
Since the outer yoke 2 and the inner yoke 3 are positioned in the circumferential direction by engaging the b with the receiving portion 2b formed on the outer yoke 2, the position of the projection 3c provided on the inner yoke 3 is appropriately determined. , The engagement of the projection 3 c with the cut 21 of the ring-shaped pole tooth 42 causes the outer yoke 2
In the circumferential direction, the pole teeth of the ring-shaped pole teeth 41 and the pole teeth of the ring-shaped pole teeth 42 of the inner yoke 3 have an electrical angle of 180 °.

FIG. 5 shows another embodiment of the positioning method according to the present invention.

In this embodiment, the circular hole 3 of the inner yoke 3
Two protrusions 3d and 3e are provided on the peripheral edge of a at positions diametrically opposed to each other (with the center of the circular hole 3a interposed therebetween), and on the other hand, at the pole piece 4A (deployed for easy understanding). Is provided with two notches 4d and 4e at the same interval as the interval between the projections 3d and 3e. When attaching the ring-shaped polar tooth portion 42 to the inner yoke portion 3, the protrusion 3d of the inner yoke portion 3
And 3e are engaged with the notches 4d and 4e of the ring-shaped pole teeth 42, respectively, so that the circumferential positional relationship between the inner yoke 3 and the ring-shaped pole teeth 42 can always be kept the same. At the same time, the projections 3d, 3e and the notches 4d, 4
Due to the abutment with e, the axial positional relationship between the inner yoke portion 3 and the ring-shaped pole teeth portion 42 can also be kept constant.

FIG. 6 shows a further development of the positioning method shown in FIG.
The point that two projections 3d and 3e are provided on the periphery of a is the same, but one of the two notches 4f provided on the pole piece 4A is
Is provided at the cut 21 of the ring-shaped pole tooth 4A, and another notch 4e is formed at the center of the pole tooth 42 in the longitudinal direction.

In this embodiment, the notch 4f is provided in the portion of the cut 21 of the ring-shaped pole tooth 42 which is not stable, and the projection 3d is brought into contact with this notch to thereby form the ring-shaped pole tooth 42 having the cut 21. Is more stable overall.

FIG. 7 shows still another embodiment of the positioning method according to the present invention.

FIG. 3A shows the inner yoke 3 in a plan view. Notches 3f, 3g are provided at diametrically opposite positions (opposing the center of the circular hole) of the periphery of the circular hole 3a. The protrusions 4g and 4h are formed on the upper edge of the ring-shaped polar tooth portion 42 at positions diametrically opposed to each other as shown in FIG. As shown in FIG. 3 (c), the ring-shaped pole teeth portion 42 is formed by punching a pole piece 4A having projections 4g and 4h spaced apart in the longitudinal direction from a side edge opposite to the pole teeth from a soft magnetic steel plate. The pole piece 4A is manufactured and then rounded.
g and 4h can be manufactured by bending outward.

FIG. 4D shows a state in which the ring-shaped polar tooth portion 42 having such a structure is attached to the circular hole 3a of the inner yoke portion 3. The engagement between the projections 4g and 4h of the ring-shaped pole teeth 42 and the cutouts 3g and 3f of the inner yoke section 3 enables the circumferential positioning of the inner yoke section 3 and the ring-shaped pole teeth 42.

In the above description, the case where the ring-shaped pole teeth 42 are attached to the inner yoke 3 has been described as an example.
The same applies to the case where the ring-shaped pole teeth 41 are attached to the outer yoke 2.

FIG. 8 is a sectional view of a stator showing another method of assembling the stator structure according to the present invention.

The bobbin 5, on which the coil 6 is wound, the inner yoke 3, the outer yoke 2, and the ring-shaped pole teeth 41, 42 are assembled, and the ring-shaped is formed by an insert molding machine using a holding jig or the like. By pouring the mold resin 28 into the pole teeth 41, 42, the ring-shaped pole teeth 41, 42 can be fixed to the outer yoke 2 and the inner yoke 3.

By using an insert molding as described above,
The pole teeth portion can be fixed to the yoke portion without mechanical attachment or welding.

Here, the outer shape of the stator structure will be further described.
The structure does not necessarily have to be a cylinder. The stator structure may be rectangular or elliptical as long as the rotor magnet fits into the limited gap. Therefore, the outer shape is made rectangular, and a space is secured inside the stator, and a mold resin is injected into the secured space to fix the A-phase stator 15 and the B-phase stator 16 while improving heat dissipation. The device may be arbitrarily designed.

[0041]

According to the present invention, a stator having a magnetic circuit composed of a stator coil, pole teeth formed of a soft magnetic steel plate, and a yoke, and a rotor magnet rotating opposite to the pole teeth of the stator are provided. In the stator structure of the claw-pole type stepping motor, the pole teeth of the soft magnetic material facing the rotor magnet are separately formed from the yoke, and are punched out of the soft magnetic steel sheet into the shape of the poles, and are then rounded to form a ring. The shape (length, width, plate thickness) of the pole teeth can be set to any shape required for the characteristics of the motor, and a small-diameter, high-output motor can be realized. In addition, the motor can be easily assembled with as few parts as possible.

[Brief description of the drawings]

1A and 1B show a stator structure of a claw-pole type stepping motor according to the present invention, in which FIG. 1A is a partially cutaway cross-sectional view showing a part of the motor, and FIG. FIG. 4 is an exploded perspective view showing a certain yoke portion and a pole tooth portion in an exploded manner.

FIGS. 2A and 2B show pole teeth used in a stator structure according to the present invention, wherein FIG. 2A is a plan view of a pole tooth manufactured by punching a soft magnetic steel plate, and FIG. 2B is a pole tooth shown in FIG. It is a perspective view of the ring-shaped pole tooth part which rounded and was manufactured.

FIG. 3 is a plan view showing one embodiment of a method for fixing a pole tooth portion to an inner yoke portion in the stator structure of the present invention.

FIG. 4 is a plan view showing another embodiment of the method of fixing the pole teeth to the inner yoke in the stator structure of the present invention.

FIG. 5 is a plan view showing still another embodiment of the method of fixing the pole teeth to the inner yoke in the stator structure of the present invention.

FIG. 6 shows a modification of the method shown in FIG.

FIG. 7 shows still another embodiment of the method of fixing the pole teeth to the inner yoke in the stator structure of the present invention;
(A) is a plan view of an inner yoke part, (b) is a perspective view of a pole tooth part, (c) is a plan view of a pole tooth piece for manufacturing the pole tooth part,
(D) is a plan view showing a state where the pole teeth are attached to the inner yoke.

FIG. 8 is a cross-sectional view for describing fixing of a pole tooth portion by insert molding.

9A and 9B are diagrams showing a stator structure of a conventional general claw-pole type stepping motor, in which FIG. 9A is a partially cutaway sectional view showing a part of the motor, and FIG. FIG. 4 is an exploded perspective view showing a yoke portion and a pole tooth portion, which are portions, in an exploded manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper flange 2 Outer yoke part 2b Receiving part 3 Inner yoke part 2a, 3a Circular hole 3b Projection 3c, 3d, 3e, 4g, 4h Projection 3f, 3g, 4d, 4e, 4f Notch 4 Polar tooth 41, 42 Ring Pole teeth 4a pole teeth 4A pole tooth pieces 5 bobbin 6 coil 7 lower flange 8 bearing 9 rotor magnet 10 sleeve 11 shaft 28 mold resin 40 soft magnetic steel plate

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toshihiko Nagata 174-1-1, Asana, Asaba-cho, Iwata-gun, Shizuoka Pref.

Claims (7)

[Claims] 1. A stator having a magnetic circuit formed by arranging a stator coil in relation to a yoke portion and a pole tooth portion manufactured by processing a soft magnetic steel plate, and rotating in opposition to the pole tooth portion of the stator. In the stator structure of a claw-pole type stepping motor comprising a rotor magnet, the pole teeth are formed as a separate part from the yoke, and are punched out of a soft magnetic steel sheet to form pole teeth to form pole teeth. A stator structure wherein the pole teeth are formed into a ring shape by rolling. 2. The stator structure according to claim 1, wherein the ring-shaped pole teeth are fitted and fixed in circular holes provided in the yoke. 3. The stator structure according to claim 1, wherein the ring-shaped pole teeth are inserted into a circular hole provided in the yoke, and both are fixed by welding. 4. The stator structure according to claim 1, wherein the ring-shaped pole teeth are inserted into circular holes provided in the yoke, and both are fixed with a mold resin. 5. The circular hole of the yoke portion is provided with a projection directed inwardly of the circular hole, and the projection is engaged with a cut of the ring-shaped pole tooth portion when fixed. Item 3. The stator structure according to any one of items 2, 3, and 4. 6. A protrusion is provided on the periphery of the circular hole of the yoke portion toward the inside of the circular hole, and a notch is provided on a periphery of the ring-shaped pole tooth portion, and the protrusion is engaged with the notch when fixed. Claims 2 and 3, characterized in that:
5. The stator structure according to any one of 4. 7. A notch is provided on a peripheral edge of the circular hole of the yoke portion, and a projection is provided on a peripheral edge of the ring-shaped pole tooth portion, so that the projection is engaged with the notch when fixed. The stator structure according to any one of claims 2, 3, and 4.